In the following phrase "Heute Abend schaue ich mir einen Film an", what is the explanation for "mir" (considering that there is a ich before) and the "an"?
(Edit: Sorry, TaylorHenrique was faster and is, of course, right; but I'll leave this here anyway...)
The basic expression is "sich etwas anschauen" - "to (have a) look at something".
You need to split the verb and put the prefix at the end of the sentence: "ich schaue ... an" ("I watch / look at ...").
Literally, the German phrase translates as "I watch myself a movie", that's where the "mir" (reflexive pronoun) comes from. You don't necessarily need the "mir", but it's the usual way to phrase it.